Various acoustic insulating materials, that is, sound insulating or sound attenuating materials, are known in the art. Acoustic insulating materials have been used in a variety of applications, for example, to reduce noise coming from running appliances and HVAC systems, to reduce the amount of noise entering buildings and/or traveling from room to room within a building, and to reduce noise entering a vehicle cabin from the outer environment and from the engine compartment, and the like. The selection of a particular acoustic insulating material is governed by several factors, including cost, desired thickness, weight and the ability to attenuate sound. Acoustic insulating materials attenuate sound by either absorbing sound waves which strike and enter the acoustic insulating material or by reflecting such sound waves outward and away from the acoustic insulating material, and often sound attenuation is achieved by both sound absorption and sound reflection.
Conventional sound insulating materials include materials such as compressed fibers, recycled fiber or shoddy materials, fiberglass or mineral fiber batts, felts and fibrous nonwoven webs such as bonded carded webs, meltblown webs, and spunbond webs. Depending on fiber size and type of fiber, such materials may also have been partly resistant to water intrusion. However, these materials have less success protecting against intrusion by low surface tension liquids such as salt-laden water, alcohols, aldehydes and ketones, and hydrophilic liquids, such as those containing surfactants or detergents or other cleaning compositions.
Where better water and low surface tension fluids intrusion protection was desired, such conventional materials have been laminated to film facing materials, such as thermoplastic films, or foil-type facing materials in order to provide a barrier to liquids. Foam acoustic insulating materials, such as for example closed cell foams, have also been known to provide fluid barrier while providing sound insulation. Moreover, closed cell foams and acoustic insulating material laminates having film or foil facings, while providing adequate fluid barrier, also tend to have extremely low breathability. That is, they tend to provide a near absolute barrier to the movement of air. In addition, the provision of additional barrier-specific layers such as film or foil facings may add an undesirable amount of expense and/or additional undesired weight to the acoustic insulating material. Furthermore, these non-porous films and foils when used as a facing may alter or degrade the acoustic performance of the acoustic insulating material.
Therefore, there exists a continuing need for acoustic insulating materials that, in addition to providing sound insulation or sound attenuation properties, also provide for repellency to water and low surface tension fluids and without deleteriously affecting the acoustic properties.